The Kelly family lives in the fictional town of Oakmoor Crossing, just before and during Halloween. The family, consisting of father David, mother Linda, and son Sean, live a normal suburban life, but are eventually visited by a stranger who identifies herself as Vivian Machen. Both the Machens and the Kellys have a long ancestral history in Oakmoor Crossing, and Vivian reveals that one of the Kelly's ancestors hanged a supposed warlock named Walter Machen, who raised up a pumpkin-headed demon, Jack-O, from hell to take revenge on the Kellys. The Kelly ancestor ended up burying the demon in a shallow grave, but through the antics of several teenagers Jack-O is raised again and seeks revenge on the Kellys.